Experience shows that the large water leakages are not always the ones resulting in the largest damages, but the small, where a few water drops are continuously discharged and then is allowed to remain hidden in walls or floors over several years and result in rot and fungus. It has also been an increasing problem with leakages where poor plumbing is the reason. Leakages also occur in many older buildings due to poor maintenance.
It is therefore a large demand for systems which are capable of detecting leakages at an early stage.
This was attempted solved in WO 9205385 which describes the use of a valve arrangement, which is connected to sensors in a room with discharge points, said sensors sending a signal to the valve arrangement which opens and closes the water supply dependent on whether persons are present in rooms with discharge points. Moreover, WO 9205385 describes the use of a pressure drop meter in order to detect leakages by comparing the pressure with a predefined value to determine whether there is a leakage or not. Using only the piping water pressure for pressure testing is not going to work over time, as one have natural leakages in piping, such as dripping from water taps, evaporation in cisterns and not at least expansions in plastic pipes in a modern pipe in pipe system. Temperature also plays an important role as water expands when heated. The hot water container is in most cases the fixed installation which affects the temperature in a pipe system the most. Most houses have a hot water container of about 120-300 liters, whereas industrial buildings, hotels and similar has one with a much higher capacity. A water container in an ordinary residence works within a temperature interval from +4 to +90 degrees. This temperature difference results in a substantial expansion in a pipe system with plastic pipes. When using the system described in WO 9205385, an expansion of this type will cause the system to detect this as a leakage and therefore produce a false alarm.
There is thus a need for a system which improves the disadvantages of the prior art.